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Using Coffee grounds for Vermicomposting

coffe groundsWhen you’re sipping your favorite cup of coffee (whether you had some brewed at home or had ordered a cup from your favorite coffee shop), did you ever wonder where these things go afterwards? Well coffee grounds can still be quite useful. Besides having to use it as part of your skin and hair regimen, or as a soil and garden supplement, you can also use these as food for your compost worms. You can read through this article to find out more about the benefits of this essential ingredient.

Grounds from your coffee are of organic matter. So instead of having to throw these away after use, you may just put in some to your composting worms bin (whether you’re into raising and breeding nightcrawler worms or red worms). Not only are you providing nourishment to your composting worms, you’re also helping mother nature experience a garbage-less environment. So you can imagine this as being a better alternative to landfill accumulation.

Besides that, when you’re using grounds from your coffee, also consider the quantity that you will put into the composter. Too much of these can come out too acidic for your worm bin, and may eventually harm or burn your worms later on (worms have very sensitive skins thus their need to be in moist surroundings at all times). So always take note of this. Now, if things get out of hand, and the worm bedding itself gets too acidic, then you can always put in some crushed eggshells to help neutralize the system.

Since compost worms also eat their bedding, you can still supplement them with some coffee (in its liquid form) when you pour some on top of it. Coffee grounds are typically dry in texture, so you might want to have these soaked in some chlorine-free water first (you can also try using some rainwater). In this way, you’re not contaminating the grounds with any kind of chemical. Now as soon as you’ve soaked these in some water, you can then use this as a liquid fertilizer. Then sprinkle some into the bedding. The worm bedding will be able to absorb this, and will then become food for your worms.

Now if you happen to be using flavored grounds from your coffee, then it shouldn’t be a problem. Your vermicomposting worms will be able to eat these since these are still recyclable matter. It’s definitely safe for your worms to eat (if humans can, why can’t they, right?). So don’t be afraid to feed your worms with some Coffee grounds. It will definitely be a good addition to their diet.

17 comments on “Using Coffee grounds for Vermicomposting

  • stefano Flocchini says:

    can you use a small amount of Plain Coffee and add it to your Worm chow????
    Not Grounds but grinded Coffee I grinded in a coffee grinder

  • Im wondering how much is too much. (aprox 8TBS daily) I currently throw all spend grounds into my outdoor bin, but I’ll be setting up my indoor living soil/earthworm habitat soon and don’t want to throw the ph off or hurt my babies! Should I use the ph meter regularly?

  • Curious if I have been using TOO MUCH coffee grounds? Asking for coffee grounds from a couple of coffee shops has brought me with an abundance and I was wondering, how much is too much?

    • Hello Harry;

      Too many coffee grounds can turn acidic and burn or harm your worms. It is best to add them in moderation. Coffee grounds should not make up more than 1/8th of your bedding material or compost. If you add too much, you can cause the pH to change drastically and this can cause a health issue for the worms. If you think that you have already added far too many coffee grounds, you should change the bedding and restart your bin so that you do not lose all of your worms.

      You can still use the bedding that you take out, but add to it and mix it well and save it for future bedding material for your worms when you harvest the castings/compost.

      We hope this information helps!

  • William Oxner says:

    Is there a difference in acidity between grounds that have been used to make coffee and grounds that have not been used? I had some old beans that were too old to make coffee, so I ground them up and added to the farm. Now I’m wondering if I should be concerned with pH.

  • I have a plastic worm ben I made with little teeny tiny holes and very top and I’ve had it probably 6 months now and now I’m having a problem with the worms trying to crawl out between the crack between the iid and the sides. And have never had that problem before what is going on. Are they needing more food, or I know they’re not too wet because I water them maybe once a week.

  • Your moisture may be off your ph may be off or they are in need of another layer of fresh food. They migrate when conditions are not ideal.

  • Wayne Mathews says:

    The worms are crawling out because they do not like their atmosphere maybe it’s too acidic maybe it’s too wet maybe it’s too hot based on what you’ve said it’s probably too acidic you want to add eggshells heat them up and grind them up and like the leader of this site said maybe you have to redo your bit bed anytime worms are crawling out it’s because they don’t like their home I ran away at 15 I know what I’m talking about LOL

  • It is a common myth that coffee grounds are acidic. USED coffee grounds are not acidic and will NOT harm worms. However, used coffee grounds are high potassium and magnesium. Using too much grounds can elevate your soil’s potassium levels which can be detrimental to plant growth. Too much potassium will inhibit the uptake of other nutrients by plants. Admittedly, I am talking about large amounts of grounds over a period of years but small to moderate amounts over years can also have the same effect. If you use used grounds as worm food, I do not know if the resulting worm castings will also have high levels of K and Mg.

  • Question… I dried my used coffee ☕️ grounds so I could store them without getting mold… are the grounds still good to put in a small container of boughten worms when you go fishing

  • Venkataramanan Nagarajan says:

    the coffee grounds i get are quite lumpy about 2-3mm in diameter. So should i dry them and powder them before adding or it can be directly put on bedding? Your response would be much appreciated.

    • Hello!
      You can add the Coffee Grounds the way they are but the worms can process smaller pieces faster as the smaller, the faster they break down. Either way, the worms will eat it all up.

    • Hello Angela;

      As With any food scraps that you put into the worm bin, the smaller the better as the smaller, the faster it breaks down and the faster the worms can process it. So ground is better, finer grounds even better.

      Uncle Jim’s Worm Farm


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